1. Field of the Invention
The present invention relates to an optical fiber cable plug for connecting an optical fiber comprising a filamentary polyamide fiber as a reinforcing fiber.
2. Description of the Related Art
As a conventional plug for an optical fiber, there is known, for example, a plug proposed by the present inventors in Japanese Utility Model Application No. 62-166744. In this plug for an optical fiber, a thread for engagement with an adaptor is formed on the wall of a plug proper on the side of a line-inserting hole, and a concave-convex portion, specifically a concave-convex portion formed by knurling, is provided on the outer periphery of the adaptor for setting and engaging a reinforcing fiber of the end portion of the optical fiber cable. This adaptor has an inner hole having a diameter larger than the outer diameter of the plug proper and a thread to be engaged with the thread formed on the plug proper is formed on the inner wall surface of the adaptor, and an annular lug having an outer diameter larger than the diameter of an inner hole of a coupling nut is formed on one end of the adaptor.
Where the coupling nut for fixing the plug proper to a flange or the like from the side of the line-inserting hole is inserted to an extent such that the coupling nut impinges against a stopper portion, the adaptor is screwed into the plug proper from the threaded portion thereof so that the lug of the adaptor impinges substantially against the side face of the coupling nut, whereby the coupling nut is rotatably set on the plug proper in the axial direction of the plug proper.
In the conventional techniques, however, the materials to be fixed are limited to a reinforcing fiber and a secondary covering, and since an optical fiber line and a primary covering can move freely within the plug, problems arise such as a turning and protrusion of the optical fiber line or the optical fiber within the plug.